LP5951MF-2.8 Equivalent & Substitute Parts

Part Overview

The LP5951MF-2.8 is a linear voltage regulator IC from Texas Instruments, delivering a fixed 2.8V output at 150mA in a SOT-23-5 surface mount package. This device is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support. The regulator features integrated protection against overcurrent, overtemperature, and short circuit conditions, with an enable control feature for power management applications.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	2.8V
Output Current	150mA
Input Voltage (Max)	5.5V
Voltage Dropout (Max)	0.35V @ 150mA
Quiescent Current	55 µA
Package Type	SOT-23-5 (SC-74A)
Operating Temperature Range	-40°C to 125°C
Protection Features	Overcurrent, Overtemperature, Short Circuit
Control Features	Enable

Substitute Part Grouping Explanation

Substitution for the LP5951MF-2.8 is determined by the following critical parameters:

Fixed output voltage of 2.8V
Output current capability of 150mA or higher
Maximum input voltage of 5.5V or greater
SOT-23-5 package compatibility
Operating temperature range of -40°C to 125°C (or compatible subset)
Enable control functionality
Overcurrent and overtemperature protection

Parts are grouped into three categories: direct equivalents (same output current), higher-current alternatives (300mA output), and manufacturer-specific variants with identical electrical specifications.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Dropout Voltage	Quiescent Current	Package	Temp Range	Product Status	RoHS Compliance
LP5951MF-2.8	Texas Instruments	2.8V	150mA	5.5V	0.35V @ 150mA	55 µA	SOT-23-5	-40°C to 125°C	Obsolete	Non-compliant
LP5951MF-2.8/NOPB	Texas Instruments	2.8V	150mA	5.5V	0.35V @ 150mA	55 µA	SOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
MIC5365-2.8YD5-T5	Microchip Technology	2.8V	150mA	5.5V	0.31V @ 150mA	39 µA	TSOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
MIC5365-2.8YD5-TR	Microchip Technology	2.8V	150mA	5.5V	0.31V @ 150mA	39 µA	TSOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
S-1312A28-M5T1U3	ABLIC Inc.	2.8V	150mA	5.5V	0.32V @ 100mA	30 µA	SOT-23-5	-40°C to 85°C	Active	ROHS3 Compliant
S-1312B28-M5T1U3	ABLIC Inc.	2.8V	150mA	5.5V	0.32V @ 100mA	30 µA	SOT-23-5	-40°C to 85°C	Active	ROHS3 Compliant
S-1312C28-M5T1U3	ABLIC Inc.	2.8V	150mA	5.5V	0.32V @ 100mA	30 µA	SOT-23-5	-40°C to 85°C	Active	ROHS3 Compliant
MIC5307-2.8YD5-TR	Microchip Technology	2.8V	300mA	5.5V	0.25V @ 300mA	30 µA	TSOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
BU28SD2MG-MTR	ROHM Semiconductor	2.8V	200mA	6V	0.15V @ 100mA	80 µA	5-SSOP	-40°C to 105°C	Active	ROHS3 Compliant
BU28UC3WG-TR	ROHM Semiconductor	2.8V	300mA	5.5V	0.22V @ 300mA	90 µA	5-SSOP	-40°C to 85°C	Not For New Designs	ROHS3 Compliant
S-1135A28-M5T1U	ABLIC Inc.	2.8V	300mA	5.5V	Not specified	1 µA	SOT-23-5	-40°C to 85°C	Obsolete	ROHS3 Compliant

Engineering Selection Recommendations

Direct Equivalent (Active Status): LP5951MF-2.8/NOPB is the direct equivalent from Texas Instruments with identical electrical specifications. This part is in active production status and ROHS3 compliant, making it the primary choice for direct replacement in new designs.

150mA Output Current Alternatives: MIC5365-2.8YD5-T5 and MIC5365-2.8YD5-TR from Microchip Technology provide identical 150mA output current with improved performance characteristics: lower dropout voltage (0.31V vs 0.35V) and reduced quiescent current (39 µA vs 55 µA). Both maintain the full -40°C to 125°C operating range and are ROHS3 compliant. The TSOT-23-5 package is mechanically compatible with SOT-23-5 footprints.

S-1312 series parts (A, B, C variants) from ABLIC Inc. deliver 150mA output with superior quiescent current performance (30 µA). Operating temperature range is limited to -40°C to 85°C. All variants are ROHS3 compliant and in active production.

Higher Current Alternatives (200-300mA): For applications requiring increased output current, MIC5307-2.8YD5-TR (300mA) and BU28SD2MG-MTR (200mA) are suitable. MIC5307 maintains the full temperature range (-40°C to 125°C) with improved dropout voltage. BU28SD2MG-MTR includes automotive qualification (AEC-Q100) with the highest input voltage rating (6V).

BU28UC3WG-TR provides 300mA output but carries "Not For New Designs" status, limiting its use to legacy system support only.

Avoid: S-1135A28-M5T1U and LP5951MF-2.8 (original) are obsolete and should not be selected for new designs despite ROHS3 compliance.

Frequently Asked Questions (FAQ)

Q: Can I use a 300mA regulator as a direct substitute for the 150mA LP5951MF-2.8? A: Yes. Higher current-rated regulators are backward compatible with lower current requirements. MIC5307-2.8YD5-TR and BU28UC3WG-TR both deliver 2.8V at 300mA and will function correctly in circuits designed for 150mA output. Verify PCB layout accommodates the package type.

Q: What is the difference between SOT-23-5 and TSOT-23-5 packages? A: TSOT-23-5 is a thin variant of SOT-23-5 with identical pin spacing and footprint compatibility. Both packages are mechanically interchangeable on standard PCBs. Microchip's MIC5365 series uses TSOT-23-5 packaging.

Q: Why is LP5951MF-2.8/NOPB listed as active when the original LP5951MF-2.8 is obsolete? A: The /NOPB suffix indicates "No Plumbum" (lead-free) packaging and represents the current production variant. Texas Instruments transitioned from the original to this RoHS-compliant version. Functionally identical, but the /NOPB variant is the supported option for new designs.

Q: Which substitute offers the best dropout voltage performance? A: BU28SD2MG-MTR provides the lowest dropout voltage at 0.15V @ 100mA, followed by BU28UC3WG-TR at 0.22V @ 300mA. MIC5307-2.8YD5-TR delivers 0.25V @ 300mA. Lower dropout voltage reduces heat dissipation and improves efficiency in power-constrained applications.

Q: Are all substitutes ROHS3 compliant? A: All active and recommended parts listed are ROHS3 compliant. The original LP5951MF-2.8 and S-1135A28-M5T1U are not compliant but are obsolete. For new designs, select only ROHS3-compliant variants.

Q: What is the temperature range limitation for ABLIC S-1312 series? A: S-1312A28-M5T1U3, S-1312B28-M5T1U3, and S-1312C28-M5T1U3 operate from -40°C to 85°C, compared to the original LP5951MF-2.8 range of -40°C to 125°C. Verify application requirements before substitution in high-temperature environments.

Q: Can I substitute the LP5951MF-2.8 with BU28SD2MG-MTR in automotive applications? A: BU28SD2MG-MTR includes AEC-Q100 automotive qualification and is suitable for automotive designs. However, verify that your specific application requirements align with its 200mA output current and -40°C to 105°C operating range.

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